This demo illustrates how to filter RadTreeList bound to LinqDataSource using a RadFilter control.

For this purpose you need to handle the ApplyExpressions event and built up the sql query manually. There you should make sure the parent items to the root for
the items fulfilling the filter criterion are returned as well. Otherwise, the filtered data set might have no any root items and as a result no records will be displayed.

The query used in this demo is universal and you can use it by replacing the columns' and the datatable's name.